Transition Metal Complexes of Phosphinous Acids Featuring a Quasichelating Unit: Synthesis, Characterization, and Hetero-bimetallic Complexes

Abstract

Diorganophosphane oxides were employed as preligands for the synthesis of catalytically active transition metal complexes of the phosphinous acids (CF3)2POH and (C2F5)2POH. Their reactions with solid PtCl2 and PdCl2 led to the formation of mononuclear phosphinous acid complexes [Cl2M{P(R(f))2OH}2] (M = Pd, Pt; R(f) = C2F5, CF3), which can be crystallized, for example, as its pyridinium salts, 2[HPy](+)[Cl2Pd{P(CF3)2O}2](2-). In vacuo HCl is liberated from the neutral palladium complexes affording mixtures of di- and polynuclear complexes. Moreover, (C2F5)2POH was reacted with several β-diketonato complexes of palladium, platinum, and nickel yielding air- and moisture-stable complexes [(acac)M{[P(R(f))2O]2H}], featuring a quasichelating phosphinous acid phosphinito unit {P(R(f))2O···H···O(R(f))2P}(-). Treatment of [Ni(Cp)2] (Cp = cyclopentadienyl) and [(cod)RhCl]2 (cod = 1,5-cyclooctadiene) with (C2F5)2POH leads to the substitution of one Cp or chloro ligand by a quasichelating unit. The novel coordination compounds were characterized by NMR and IR spectroscopies, mass spectrometry, and X-ray diffraction analysis. The platinum complex [(acac)Pt{[P(C2F5)2O]2H}] (acac = acetylacetonato) was used for the construction of hetero-bimetallic complexes by the treatment with [(cod)RhCl]2 and [Ni(Cp)2]. The trinuclear bimetallic complex [{(acac)Pt[P(C2F5)2O]2}2Ni] is the first structurally characterized hetero-bimetallic species containing a bis(perfluoroalkyl)phosphinito bridge.

Phosphinous Acid Platinum Complex as Robust Catalyst for Oxidation: Comparison with Palladium and Mechanistic Investigations

“…Likewise, P–Pt–P angles values are consistent with those reported for similar complexes bearing either PAs or bidentate phosphines, as ligands. Finally, the short distances between the two oxygen atoms of the PA ligands [O(1) O(2): 2.389 Å, O(5) O(6): 2.398 Å] suggest a strong H–O–H bonding .…”

Coordination Properties of Perfluoroethyl‐ and Perfluorophenyl‐Substituted Phosphonous acids, RfP(OH)2

“…[6] An explanation fort his different reactivity could be the decreased stericd emando ft he OH group compared with that of the pentafluoroethyl group. [6] An explanation fort his different reactivity could be the decreased stericd emando ft he OH group compared with that of the pentafluoroethyl group.…”

Synthesis of Pt(ii) phosphinocarboxylate complexes with auxiliary arylcarbene ligands and factors that control their stereochemistry

“…1 In this way, the readily accessible acetylacetonate complexes can serve as convenient precursors of diverse transition metal compounds. 2 Examples include products obtained through reactions between palladium(II) acetylacetonate and imidazolium salts to produce carbene complexes 3 as well as analogous reactions with oxalic amidinates, 4 2,5-diamino-1,4-benzoquinonediimine, 5 1-(isoquinolin-1-yl)-2-naphtholes, 6 and porphyrins bearing enaminoketone moieties at the periphery, 7 or reactions between the corresponding platinum(II) complex and secondary phosphine oxides 8 or benzoquinonediimines. 9 Reactions of acetylacetonate complexes with protic difunctional proligands (X^YH) that produce X,Y-chelate complexes are particularly attractive.…”